METHOD FOR CONTROLLING A HYDRODYNAMIC RETARDER WHICH CAN BE MECHANICALLY DECOUPLED VIA A SEPARATION COUPLING

The invention relates to a method for controlling a hydrodynamic retarder that can be mechanically decoupled via a disconnecting clutch in a motor vehicle, which has a rotating vaned rotor and a vaned stator or a rotating vaned rotor and a counter-rotating vaned counter rotor which together form a work space filled with working medium during braking operation and emptied of working medium during non-braking operation, wherein the rotor is driven via a drive train with a closed disconnecting clutch during braking operation and during the transition from braking operation to non-braking operation the work space is emptied and the disconnecting clutch is opened, wherein the transition from braking operation to non-braking operation is initiated by a retarder deactivation request of a driver assistance system or by actuation of an input device by a vehicle operator, and the transition from non-braking operation to braking operation is initiated by a retarder activation request of the driver assistance system or by actuation of an input device by the vehicle operator. [0002] The method according to the invention is characterized in that regardless of the retarder activation request of the driver assistance system or by actuation of the input device by the vehicle operator, the disconnecting clutch is closed at the beginning of a start-up process of the motor vehicle when the work space is filled with working medium during standstill of the motor vehicle.